1. Field of the Invention
This invention relates to a method and apparatus for separating molecules. More particularly, the present invention is a method and apparatus for separating a gaseous mixture of different molecules based on their polarities.
2. Discussion of Background
Molecules may be separated from each other in a number of different ways, both chemically and physically. Typically, the separation technique selected can be a chemical one provided that the chemical characteristics are different. However, there are a number of situations where molecules are indistinguishable chemically but are in fact different physically and need to be separated. Examples of such molecular mixtures include diatomic combinations of the isotopes of hydrogen: protium, deuterium and tritium. Usually the physical differences are slight--perhaps amounting to a single neutron--and therefore the processes known for such separation are painstaking.
A molecule may have a transition dipole moment, if it is a polar molecule. The electrons of such a polar molecule occupy discrete energy levels, which depend on the energy of the molecule that change when the molecule gains or loses energy. The dipole moment of the molecule depends on the charge distribution associated with these electrons. Since the charge distribution will vary with absorbed energy, the transition dipole moment, the magnitude of the dipole moment will change accordingly. The dipole moment will also be different for each molecule because the energy states of molecules are affected by the presence of different numbers of nuclides in each molecular constituent.
Energy is absorbed by molecules in discrete amounts, or quanta, that are related to specific frequencies of electromagnetic energy; in other words, there are particular frequencies, "resonant" frequencies, of electromagnetic energy that are much more likely to be absorbed by particular molecules than other frequencies. Also, when molecular energy is radiated, rather than absorbed, by molecules, distinct energy quanta are emitted, quanta whose magnitude depends on the rotational energy level separations and dipole moments.
Conventional distillation is a process that consists of driving gas or vapor from liquids or solids by heating and condensing to liquid products and that is used for purification, fractionation, or the formation of new substances. The basic property which allows the separation of the constituents in a mixture is the boiling point of the components.
Selective laser-induced excitation is a process for separating a dissolved gas, such as deuterium or tritium, from water. Dissolved gas and water are heated into a vapor, mixed with ethylene, and simultaneously irradiated with light from two lasers. The lasers operate at different frequencies so as to selectively excite different molecular species while ignoring other species. Jenson in U.S. Pat. No. 3,904,500, describes operating a laser in the ultraviolet and infrared frequencies.
Microwave ovens have been used as energy sources to cook food, dry samples, react chemicals, etc. However, their industrial applications at the molecular level have not been fully realized.
It is clear that many techniques are available for separating hydrogen isotopes. However, there remains a need for a method and apparatus for separating hydrogen isotopes that is much more efficient.